AuxXxilium/linux_dsm_epyc7002
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2 Commits

Author SHA1 Message Date
Josh Poimboeuf
e2391a2dca livepatch: Fix crash with !CONFIG_DEBUG_SET_MODULE_RONX 
When loading a patch module on a kernel with
!CONFIG_DEBUG_SET_MODULE_RONX, the following crash occurs:

  [  205.988776] livepatch: enabling patch 'kpatch_meminfo_string'
  [  205.989829] BUG: unable to handle kernel paging request at ffffffffa08d2fc0
  [  205.989863] IP: [<ffffffff8154fecb>] do_init_module+0x8c/0x1ba
  [  205.989888] PGD 1a10067 PUD 1a11063 PMD 7bcde067 PTE 3740e161
  [  205.989915] Oops: 0003 [#1] SMP
  [  205.990187] CPU: 2 PID: 14570 Comm: insmod Tainted: G           O  K 4.1.12
  [  205.990214] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.8.1-20150318_183358- 04/01/2014
  [  205.990249] task: ffff8800374aaa90 ti: ffff8800794b8000 task.ti: ffff8800794b8000
  [  205.990276] RIP: 0010:[<ffffffff8154fecb>]  [<ffffffff8154fecb>] do_init_module+0x8c/0x1ba
  [  205.990307] RSP: 0018:ffff8800794bbd58  EFLAGS: 00010246
  [  205.990327] RAX: 0000000000000000 RBX: ffffffffa08d2fc0 RCX: 0000000000000000
  [  205.990356] RDX: 01ffff8000000080 RSI: 0000000000000000 RDI: ffffffff81a54b40
  [  205.990382] RBP: ffff88007b4c4d80 R08: 0000000000000007 R09: 0000000000000000
  [  205.990408] R10: 0000000000000008 R11: ffffea0001f18840 R12: 0000000000000000
  [  205.990433] R13: 0000000000000001 R14: ffffffffa08d2fc0 R15: ffff88007bd0bc40
  [  205.990459] FS:  00007f1128fbc700(0000) GS:ffff88007fc80000(0000) knlGS:0000000000000000
  [  205.990488] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [  205.990509] CR2: ffffffffa08d2fc0 CR3: 000000002606e000 CR4: 00000000001406e0
  [  205.990536] Stack:
  [  205.990545]  ffff8800794bbec8 0000000000000001 ffffffffa08d3010 ffffffff810ecea9
  [  205.990576]  ffffffff810e8e40 000000000005f360 ffff88007bd0bc50 ffffffffa08d3240
  [  205.990608]  ffffffffa08d52c0 ffffffffa08d3210 ffff8800794bbed8 ffff8800794bbf1c
  [  205.990639] Call Trace:
  [  205.990651]  [<ffffffff810ecea9>] ? load_module+0x1e59/0x23a0
  [  205.990672]  [<ffffffff810e8e40>] ? store_uevent+0x40/0x40
  [  205.990693]  [<ffffffff810e99b5>] ? copy_module_from_fd.isra.49+0xb5/0x140
  [  205.990718]  [<ffffffff810ed5bd>] ? SyS_finit_module+0x7d/0xa0
  [  205.990741]  [<ffffffff81556832>] ? system_call_fastpath+0x16/0x75
  [  205.990763] Code: f9 00 00 00 74 23 49 c7 c0 92 e1 60 81 48 8d 53 18 89 c1 4c 89 c6 48 c7 c7 f0 85 7d 81 31 c0 e8 71 fa ff ff e8 58 0e 00 00 31 f6 <c7> 03 00 00 00 00 48 89 da 48 c7 c7 20 c7 a5 81 e8 d0 ec b3 ff
  [  205.990916] RIP  [<ffffffff8154fecb>] do_init_module+0x8c/0x1ba
  [  205.990940]  RSP <ffff8800794bbd58>
  [  205.990953] CR2: ffffffffa08d2fc0

With !CONFIG_DEBUG_SET_MODULE_RONX, module text and rodata pages are
writable, and the debug_align() macro allows the module struct to share
a page with executable text.  When klp_write_module_reloc() calls
set_memory_ro() on the page, it effectively turns the module struct into
a read-only structure, resulting in a page fault when load_module() does
"mod->state = MODULE_STATE_LIVE".

Reported-by: Cyril B. <cbay@alwaysdata.com>
Tested-by: Cyril B. <cbay@alwaysdata.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
 2015-11-06 11:10:03 +01:00
Seth Jennings
b700e7f03d livepatch: kernel: add support for live patching 
This commit introduces code for the live patching core.  It implements
an ftrace-based mechanism and kernel interface for doing live patching
of kernel and kernel module functions.

It represents the greatest common functionality set between kpatch and
kgraft and can accept patches built using either method.

This first version does not implement any consistency mechanism that
ensures that old and new code do not run together.  In practice, ~90% of
CVEs are safe to apply in this way, since they simply add a conditional
check.  However, any function change that can not execute safely with
the old version of the function can _not_ be safely applied in this
version.

[ jkosina@suse.cz: due to the number of contributions that got folded into
  this original patch from Seth Jennings, add SUSE's copyright as well, as
  discussed via e-mail ]

Signed-off-by: Seth Jennings <sjenning@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
 2014-12-22 15:40:49 +01:00